DTC P0137 [LF]: Notes
DTC P0137 (LF) DETECTION CONDITION AND POSSIBLE CAUSE
| DTC P0137 |
HO2S circuit low input |
| DETECTION CONDITION |
- The PCM monitors input voltage from HO2S. If the input voltage from the HO2S is below -0.95
V or HO2S bias voltage below 1.2 V
for 5 s
while the HO2S is active, the PCM determines that the HO2S circuit input is low.
Diagnostic support note
- This is a continuous monitor (A/F sensor, HO2S).
- The MIL illuminates if the PCM detects above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM.
- PENDING CODE is available if the PCM detects the above malfunction condition during the first drive cycle.
- FREEZE FRAME DATA (Mode 2/Mode 12) is available.
- The DTC is stored in the PCM memory.
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| POSSIBLE CAUSE |
- HO2S connector or terminals malfunction
- Short to ground in wiring harness between HO2S terminal A and PCM terminal 20.
- PCM connector or terminals malfunction
- Open circuit in wiring harness between HO2S terminal A and PCM terminal 2Q
- Open circuit in wiring harness between HO2S terminal B and PCM terminal 2BH
- HO2S malfunction
- PCM malfunction
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 Courtesy of MAZDA MOTORS CORP.
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